SIGNIFICANCE: The trials resulted in successful prosecutions for the bombing of the World Trade Center, the first large-scale terrorist attack in the United States of the 20th century.

The tremor felt by tourists at the Statue of Liberty on February 26, 1993, was not an earthquake. The shudder reaching across New York Harbor was the shock of a bomb smashing four underground levels of the World Trade Center, shaking the twin towers of the 110-story complex. Electricity and elevators were cut off, leaving hundreds of office workers and visitors huddling in terror or struggling down dark stairways choked with black smoke.

Six people were killed and over 1,000 were injured by the blast. The United States had seemed immune from such terrorist attacks until this explosion. As a chill of vulnerability touched the nation's cities, investigators crept into the teetering rubble of the World Trade Center's basement, looking for clues.

Van Deposit Leads to Arrests

Forensic investigators soon determined that the blast was caused by common explosives, detonated in a yellow van. They found the vehicle's charred
identification number and traced it to a Ryder Rental Company agency in New Jersey. A few days later, the man who had rented the van told a federal agent posing as a rental clerk that the vehicle had been stolen. When the "clerk" refused to return a $400 deposit, the customer left in a huff. Federal agents grabbed him at a nearby bus stop and held him without bail.

The suspect was Mohammed Salameh, a Jordanian living in the United States with an outdated tourist visa. Other arrests quickly followed. Nidal Ayyad, a chemical engineer whose business card was discovered in Salameh's pocket, was also taken into custody. Bilal Alkaisi, who shared a joint bank account with Salameh and Ayyad, surrendered to the FBI. A fourth man, Mahmud Abouhalima, was arrested in Cairo and deported to the United States to face indictment. Abouhalima showed signs of having been tortured by Egyptian police. His American lawyer, William Kunstler, argued unsuccessfully that any admissions obtained by Egyptian authorities from Abouhalima were gotten under duress and should be ruled inadmissible. A fifth suspect, Ibrahim Elgabrowny, was accused of carrying false passports and resisting arrest. He was indicted with Salameh and Ayyad on March 19.

A Palestinian, Ahmad Ajaj, was also arrested, on May 6, 1993. The previous year, he had been detained at Kennedy International Airport for having a doctored passport and military manuals containing bomb-making instructions. After six months in detention, he had been released. When investigators learned
that he had traveled to the United States on the same flight as Ramzi Ahmed Yousef—another suspect who had been seen with Salameh in the yellow van and whose fingerprints were found on the pages of the manuals in Ajaj's luggage—Ajaj was arrested again. Yousef, in the meantime, had disappeared. The FBI placed him on its 10-Most-Wanted list and a $2 million reward was offered for information leading to his arrest.

Far-Reaching Conspiracy Alleged

Ajaj, Ayyad, Salameh, and Abouhalima were charged with a total of 38 crimes, including explosive destruction of property, conspiracy, and interstate transportation of explosives. All the suspects except Ajaj were followers of Sheik Omar Abdel Rahman, a blind cleric who preached militant Islamic doctrine from a Jersey City storefront mosque. In late August 1993, Sheik Abdel Rahman and a dozen of his adherents were indicted for plotting "a war of urban terrorism against the United States." Under a rarely used seditious conspiracy law, the sheik was accused of guiding the group, whose alleged targets included the United Nations, New York's FBI office, and the Holland and Lincoln Tunnels connecting New York with New Jersey. The defendants were also accused of planning to kill Egyptian President Hosni Mubarak and American politicians sympathetic to Israel.

Federal authorities declared that the World Trade Center bombing was one of the violent acts within this wider conspiracy. Salameh, Ayyad, Abouhalima, and Ajaj were named as coconspirators in the new case, but no fresh charges were added to those they already faced when their trial began on September 14, 1993. Judge Kevin T. Duffy was sufficiently concerned that publicity about the bombing had been so pervasive that he ordered an extra 5,000 jury duty summonses to be mailed. In fact, a jury was selected in less than a week.

Although none of the accused men had been seen at the site of the explosion, prosecutors attempted to tie them to the crime by sheer weight of circumstantial evidence. An entire month crawled by as hundreds of forensic exhibits were introduced, ranging from macabre photos of dead victims to dry architectural analyses of the World Trade Center's internal structure.

Defendants Tied to Van, Bomb Manuals

Testimony eventually got around to the defendants themselves. Prosecutors produced as evidence the frame of a vehicle that experts placed at the very center of the explosion. The serial number on the charred metal matched that of the yellow Ford van rented by Salameh. Bank officers testified that Salameh and Ayyad shared a joint account funded by undetermined overseas sources. A Jersey City chemical supplier relayed that Salameh and the fugitive, Yousef, had bought thousands of dollars of raw materials, which experts identified as primary components used in homemade bombs. Other witnesses recalled Ayyad ordering
tanks of compressed hydrogen gas, which were delivered to a storage locker rented by Salameh and Yousef. When the storage company asked the renters to remove the tanks, the canisters were picked up by a yellow van.

A gas station attendant recalled two customers filling a yellow van's gas tank on the morning of the blast. When asked to identify the men in court, however, the attendant pointed to two jurors. The witness identified Abouhalima and Salameh when he returned to court the next day. Apart from this tenuous connection, the only physical evidence against Abouhalima consisted almost entirely of sulfuric acid burns on shoes found in his home. Prosecutors noted that the chemical could be used to make bombs. Hassen Ibn Abdellah, Abouhalima's attorney, pressed witnesses to admit that the substance could as easily have come from a car battery.

The New York Times received a letter from the Liberation Army Fifth Battalion claiming responsibility for the bomb after the blast occurred. DNA testing confirmed with a 97 percent probability that Ayyad's saliva had sealed the envelope. No such scientific evidence was offered in the case against Ajaj. The government, however, contended that Ajaj's possession of military manuals containing bomb-making instructions was sufficient proof of his complicity.

Austin Campriello, Ajaj's attorney, argued that possession of the manuals had resulted in his client's detention by immigration authorities on September 1, 1992 and therefore could not have been used in the bombing plot.

"What he slid over," Campriello said, faulting lead prosecutor J. Gilmore Childers's view of the confiscated manuals, "was that [Ajaj's] material was taken from him that very day and was in the possession of the United States government until the very day the World Trade Center tragedy occurred."

During four months of testimony from 207 witnesses, defense attorneys offered no rebuttal witnesses or evidence of their own. None of the defendants testified on his own behalf.

Verdicts Are Read

During closing arguments, Salameh's lawyer unexpectedly claimed that his client had been manipulated into unwittingly participating in the plot by the fugitive, Yousef. However, defense attorney Robert Precht's gamble did not pay off. After less than a week of deliberations, the defendants were found guilty of all 38 charges.

The defendants dismissed their lawyers while awaiting sentencing. When they returned to court on May 24, 1994, all four were allowed to give statements.

Speaking in Arabic, each defendant protested that the trial was unfair. Salameh, Ayyad, and Abouhalima each gave long, angry political speeches, expressing their distaste for American society and their support for Islamic extremist movements around the globe. Unlike the others though, Ajaj called the bombing "a horrible crime." He then spoke for over two hours about
atrocities committed against the Palestinian people. After witnessing and suffering from such violence, he said, he had no wish to act violently toward anyone.

Judge Duffy eventually cut him off. "All you've done in the past two and a half hours is convince me that anything you say is either a reworking of the truth or an out-and-out lie.… You were in this plot up to your ears."

Although all of the crimes in the case were serious, none was punishable by terms of life imprisonment under New York law. When the judge passed sentence, however, it was clear that the convicted men would spend the rest of their lives in prison.

The judge subtracted the ages of each of the six dead victims from an average life expectancy of 60 years. Together, according to this formula, the deceased had been denied a total of 180 years of possible life. To this sum, the judge added mandatory 30-year penalties for each of the two convictions of assault on a federal officer. The defendants were thus sentenced to 240 years in prison each, with no possibility of parole.

Ajaj appealed his conviction with the help of a new court-appointed attorney. Looking again at one evidentiary notebook on explosives, upon which the government had built much of its case, analysts found that Ajaj's handwriting did not match the incriminating notations in the book.

Ajaj also claimed that he had been planning to mail the other military manuals in his possession to the family of a Jordanian, who had been killed
fighting in Afghanistan. He pointed out that the books were only part of a bundle of mail he had agreed to post for other Arabs he had met in Pakistan, whose mail systems to other countries were not as reliable as those of the U.S. Postal Service. Ajaj admitted that he had met Yousef, but insisted that the fugitive had neither revealed his real name nor spoken of any violent intentions.

Philippine Airline Plot

In the ensuing years, other figures in the wider conspiracy alleged by the government were brought to trial. Sheik Rahman was convicted on October 1, 1995, on conspiracy counts brought under the sedition charge and sentenced to life imprisonment without parole. During the sheik's trial, Ramzi Yousef was arrested in Pakistan and extradited to the United States. The indictment against him was so complicated that Judge Duffy divided the charges against Yousef into two separate court cases.

Before Yousef could face trial in the World Trade Center case, however, he stood accused of a potentially bloodier terrorist plan. Prosecutors charged that Yousef, Pakistani pilot Abdul Hakim Murad, and Wali Khan Amin Shah had conspired to detonate bombs aboard a dozen commercial airliners during a 48-hour period in January 1995. By killing an estimated 4,000 passengers en route from the Philippines to Los Angeles, San Francisco, Honolulu, and New York, the bombers hoped to force the United States to end aid to Israel. Shah was accused of testing a timer by leaving a bomb in a Manila theater on December 1, 1994. Yousef was charged with hiding a bomb on a Philippine Airlines flight to Tokyo on December 11 in a similar test; the bomb killed a Japanese passenger and injured 10 others.

Philippine police discovered the airline plot on January 6, 1995, when chemicals Yousef and Murad were mixing started a fire in a Manila apartment. Yousef fled to Pakistan, but Murad was arrested when he returned, allegedly to dispose of nitroglycerine, timers, bomb-making equipment, and manuals, as well as a computer containing details of the plot.

The three defendants pleaded not guilty when the trial began on May 13, 1996. They claimed they were beaten while in custody and that they had not been properly informed of their rights when they gave statements to FBI agents while being transported to the United States to face trial. The incriminating statements included a detailed account by Yousef of how the World Trade Center bomb was made and delivered. The FBI agents also claimed that Yousef had boasted of plots to assassinate Pope John Paul II and President Bill Clinton.

Judge Duffy, also presiding in the Philippine Airlines plot, ruled that these disputed statements were admissible at the trial and rejected a defense motion that the United States did not have jurisdiction in the airline case. Although the plot was to have been executed from the Philippines, Duffy pointed out that U.S. law allowed prosecuting any crime taking place aboard an international aircraft.

In addition to Yousef's admissions and voluminous bomb-related evidence linked to the trio, the most damaging exhibit was the laptop computer found in the Manila apartment. Under the file name "Bojinga," the computer's contents included the targeted jets' flight schedules, money transfers, identification photographs, and a threatening letter explaining that the attack was a response to U.S. financial, political, and military assistance to Israel.

Over the objections of his codefendants' attorneys and warnings from Judge Duffy, Yousef dismissed his court-appointed lawyer, Roy Kulcsar (who would represent Yousef later in the World Trade Center bombing trial). Yousef argued that he had been detained and tortured by Pakistani security forces in November 1994 when he was allegedly organizing the airline plot in Manila, but was contradicted by prosecution records showing that he was not arrested in Pakistan until February 1995.

With little apparent success in forwarding his defense, Yousef crossexamined an airline attendant who identified him as sitting in the seat later taken by the airline bomb victim. He declared that the evidence against him had been fabricated by the Philippine and Pakistani governments. Shah's and Murad's lawyers repeated this charge, pointing to testimony in which Manila investigators admitted filing false reports to justify searching the fire-damaged apartment where the evidence was discovered. Because the search had taken place in the Philippines and was not subject to U.S. rules of evidence, however, the discovery was ruled legitimate.

Boastful Admissions

On September 5, 1996, a jury found the three defendants guilty on all of the counts against them. Before they were sentenced, however, Yousef stood trial for complicity in the World Trade Center plot. When that trial began on August 3, 1997, Yousef's codefendant was a former schoolmate and chemical engineer named Eyad Ismoil. Prosecutors accused Ismoil of driving the explosive-laden van into the World Trade Center's underground garage and helping Yousef set the fuse. Ismoil had flown to Jordan that night, but was later arrested and extradited to the United States. Ismoil pleaded his innocence and protested that he thought the van contained only soap and shampoo.

Prosecutors ridiculed Ismoil's claim. For two months they introduced forensic testimony about residue and fingerprints found at bomb-making sites in New Jersey; telephone receipts; and other evidence linking both defendants to a Jersey City apartment where the bomb had been made.

The most damaging testimony against Yousef stemmed from his alleged boasting to American agents on his flight back to the United States from Pakistan. Aboard the plane, Yousef allegedly claimed that he had masterminded the plot and had initially considered mounting a poison gas attack. He hoped the bomb would topple one Trade Center tower into the other and kill at least 250,000 people. He was disappointed in the results of the blast, but stood on the
New Jersey waterfront to watch the smoke from the fire across the river before he fled the country.

Neither of the defendants took the witness stand in their own defense, leaving the arguments to their lawyers. Defense attorney Kulcsar characterized Yousef's alleged admissions of guilt as illogically self-incriminating. Kulcsar wondered why the damaging confessions had never been recorded. Ismoil's attorney, Louis Aidala, admitted that his client had helped load the van but had been ignorant of its deadly contents.

Final Sentences

On November 12, 1997, Yousef and Ismoil were convicted on all the charges against them, including the lethal use of explosives, which carried a mandatory sentence of life imprisonment without parole. On January 8, 1998, Yousef was sentenced to life imprisonment without parole for participating in the World Trade Center bombing, the airline conspiracy, and causing the death of the Japanese passenger in the latter plot's "test run." Murad received a life sentence and was fined $250,000 so that he could not profit from the case. Shah began cooperating with authorities and was rumored to provide information about Saudi militant Osama bin Laden, whom U.S. authorities accused of being the mastermind behind explosions at two American embassies in Africa on August 7, 1998. Ismoil received a 240-year sentence calculated by the same formula Judge Duffy used in the first bombing trial, plus heavy fines that ensured Ismoil would never profit financially from telling his story.

The World Trade Center trials resulted in the prosecution of all but one of the accused participants, Abdul Rahman Yasin, whom federal authorities had detained but carelessly released after the blast. Yasin was thought to have escaped to Iraq. Despite the trials and convictions, the mystery of who financed the attack, however, still remains.

—TomSmith

Suggestions for Further Reading

Childers, J. Gilmore. Statement before the U.S. Senate Judiciary Committee Subcommittee on Technology, Terrorism, and Government Information, "Foreign Terrorists in America: Five Years after the World Trade Center" hearing. February 24, 1998. http://judiciary.senate.gov/childers.htm.

World Trade Center, 2001 Terrorist Attack

Encyclopedia of Espionage, Intelligence, and Security
COPYRIGHT 2004 The Gale Group Inc.

World Trade Center, 2001 Terrorist Attack

█ JUDSON KNIGHT

At 8:46 a.m. on September 11, 2001, American Airlines Flight 11, hijacked from Boston's Logan Airport with 92 people on board, crashed into the upper floors of the World Trade Center north tower in lower Manhattan, New York. Seventeen minutes later, United Airlines Flight 175, also hijacked from Logan and with 65 people on board, crashed into the south tower. By this time, virtually the entire nation had tuned in to witness the after-effects on television of what at first seemed a terrible accident, but was quickly revealed as a terrorist attack. Over the course of the next 85 minutes, the south tower collapsed, followed by the collapse of the north tower. The incident, in which nearly 3,000 people died, ranks as by far the worst case of mass murder in U.S. history, the worst building disaster in human history, and the largest terrorist incident in the history of the western world.

The Towers and their Environment

Designed by architect Minoru Yamasaki—who, ironically, had a fear of heights—and engineered by Leslie Robertson and John Skilling, the 110-story towers soared 1,360 feet (415 m) above an open plaza, which made them the world's tallest buildings at the time of their completion in 1973. Whereas the Empire State Building and other older skyscrapers drew support from an interior grid of steel girders, support for the trade towers came from the exterior and the inner core. Horizontal floor trusses joined the perimeter support structure to the central area, which the engineers envisioned as a great "tube" running through the building and containing not only its support structure, but also its utilities such as elevators. This design had two advantages; it made the buildings extremely stable—not prone to swaying in high winds as the Empire State did—and it left much of the interior available as rentable space.

To support such a structure required a strong foundation, and in this regard, the location in lower Manhattan was not a promising one. Bedrock lay between 55 and 80 feet (17–24 m) below street level, and to get to it, construction crews had to deal with another engineering challenge: flooding from the nearby Hudson River. In order to dig without flooding the site, they dug narrow trenches to the bedrock, and as they went, they pumped in a slurry of water and bentonite, a type of clay that expanded to prevent groundwater from flowing in. The slurry trench method made it possible to build a watertight framework for the excavation of the foundation structure, nicknamed "the bathtub."

Excavation began in 1966, and yielded such a quantity of fill that it was used to reclaim 28 acres (11.3 hectares) from the Hudson to form Battery Park City. In addition to supports, in the area underneath the buildings would be seven stories of parking decks, stores, and subway lines. The erection of the buildings themselves, which took more than five years, was a massive feat of both construction and logistics, involving 200,000 tons (181,437) of steel, each major piece of which was marked with an identification number. Over the years of building, many businesses moved in long before the towers were officially completed.

28 years in the towers' lives. On April 4, 1973, the World Trade Center officially opened for business. Though the towers were by far the most notable aspect of the project, they were just two of seven buildings in the entire complex. Built at a cost of $1 billion, the towers functioned as virtual cities unto themselves, with some 500 businesses, including banks and their offices, law firms, brokerage houses, television stations, charitable organizations, airlines, and government offices. Supporting these functions and the 50,000 employees who filled them were numerous restaurants—most notable of which was "Windows on the World" at the top of the North Tower—as well as other services, including nine chapels of different faiths.

By the 1980s, New Yorkers had become accustomed to the trade towers, which punctuated the skyline as the ultimate symbol of American commerce. Then, in February 1993, just months before the towers turned 20, the towers became the target for a bombing by Islamist terrorists operating a van filled with explosives. In this, the first terrorist attack, six people were killed, but the structural integrity of the towers themselves was not threatened.

September 11 and Its Aftermath

Because of the 1993 attack, many Americans who witnessed the events of September 11, 2001, quickly realized that the buildings had once again become the target for terrorists. When Flight 11 crashed into the North Tower of the World Trade Center at 8:46 a.m., smoke and flames began to gush from the upper stories, and workers began to evacuate the lower floors. Some, however, chose to remain at their desks. For workers on the floors above the impact area, there was no choice but to remain in place.

For 17 minutes, it was possible to assume that what had happened to the North Tower was an accident; then, Flight 175 smashed into the South Tower. Once again, smoke and flames erupted from the heights of the building, and tenants down below began a slow, but steady evacuation while others—many with no choice—stayed where they were.

By 9:59 a.m., millions of Americans had turned on their television sets to watch live reports from the site. Thus, there was a vast audience to experience what happened next, an event that would be etched upon the consciousness of an entire nation. With little warning, the South Tower, succumbing to the stress caused by the fire, began to crash from the top down, creating a vast cloud of dust and ash above and filling the streets below with noise and heat and terror.

By 10:28 a.m., the North Tower began to implode, once again crashing downward from the top, and the area around what had once been the World Trade Center became smoke, ash, and dust. The other five buildings in the former World Trade Center complex, including the Marriott Hotel, the Commodities Exchange, Dean Witter, the U.S. Customs House, and 7 World Trade Center, were destroyed as well. The last of these caught fire, and collapsed that night.

Rescue, cleanup, and the death toll. In the next days and weeks, some 1,500 firemen, search and rescue workers, ironworkers, engineers, heavy equipment operators, and others labored at the site where the towers had stood, a place now known variously as "Ground Zero" or "the Hole." In the shock and horror that followed the attacks, among the few bright spots were the many tales of heroism told by people who owed their lives to police, fire, and medical personnel.

That heroism continued in the weeks of the cleanup, as rescue workers sifted through piles of wreckage. The purpose of their job was manifold. Not only were they cleaning the site, but they were looking for evidence, and—most poignantly—for any signs of the dead.

At first, rescuers had hoped to find survivors trapped under the rubble and trauma centers at local hospitals braced to treat mass casualties, but those hopes faded quickly, and the cleanup work involved sifting through materials that included physical traces of the building's former inhabitants. Not only was the cleanup work grisly, it was also dangerous: rather than working on solid ground, the rescuers had to set up their cranes and other equipment on top of debris piled several hundred feet above the buildings' foundations.

The numbers of the dead would emerge slowly, and had yet to be fully authenticated even two years later. Although the dead numbered 2801, it was estimated that at the early morning hour, almost 7000 of the 50,000 people who worked in the buildings were in their offices at the time of the attacks. Although the span of time between the attacks and the collapse of the buildings was little more than an hour, it had been enough for those who were able to do so to evacuate via stairwells.

Structural explanations. In late 2001, a team of investigators that included representatives of the American Society of Civil Engineers and the Federal Emergency Management Agency (FEMA) commenced a study on the structural collapse of the towers, the details of which they made public in April 2002. In August 2002, the National Institute of Standards and Technology (NIST) began its own study, scheduled to last two years.

The first team concluded that it was not the impact, but the heat from the burning jet fuel, that heated the temperature of the buildings' steel support structures up to 800°C (1472°F), causing them to buckle and the floors to collapse downward. (Both jets were bound for Los Angeles and had almost a full complement of fuel on board.) On the other hand, the impact did have the effect of knocking out support columns in the building's interior, which may have weakened the structure. The initial crash neutralized sprinkler systems, allowing spread of the fire, which was fed by caches of paper and other flammable materials in offices.

Almost all sources, including government officials, architects, and engineers, agreed on key elements of the building damage. First, it would have been virtually impossible to prevent the destruction of the buildings by aircraft used in the way they were on September 11 as guided missiles. Second, the structural integrity of the buildings that allowed the towers to stand for over an hour after the impacts enabled thousands of people to evacuate. Finally, it was evident that the era of the extremely tall skyscraper was in question. Due to high costs, the construction of very tall buildings had been on the decline in the United States for many years, and the events of 9/11 sealed the fate of some mega-skyscraper projects.

The perpetrators. Federal authorities, using financial records and other materials, had long since identified the al-Qaeda terror network as the perpetrators of the attack. Al-Qaeda was not a new name: it and its leader, Osama bin Laden, had been linked with the August 1998 bombings at U.S. embassies in Africa, and with the bombing of the USS Cole in Yemen in 2000.

Al-Qaeda had strong links to the Taliban regime in Afghanistan, which gave them asylum. Officials in the administration of President George W. Bush, as well as some observers outside the administration, also held that there were substantive links between al-Qaeda, the terrorists who carried out the 1993 bombing, and the government of Iraq. (In fact, Ramzi Youssef, one of the ring leaders in 1993, was nephew to Khalid Sheikh Mohammed, a top al-Qaeda operative, and considerable evidence—including Youssef's Iraqi passport—linked them to Iraq.) The U.S. military actions against Afghanistan in 2001–2002, and Iraq in 2003, were a response to the 2001 terrorist attacks, whose most potent images revolved around the collapse of the World Trade Center towers.

█ FURTHER READING:

BOOKS:

Halberstam, David. New York September 11. New York: Power House Books, 2001.

Hoge, James F., and Gideon Rose. How Did This Happen?: Terrorism and the New War. New York: PublicAffairs, 2001.

World Trade Center, 1993 Terrorist Attack

Encyclopedia of Espionage, Intelligence, and Security
COPYRIGHT 2004 The Gale Group Inc.

World Trade Center, 1993 Terrorist Attack

█ JUDSON KNIGHT

The World Trade Center (WTC) bombing of 1993 has long since been overshadowed by the attack that brought the twin towers down on September 11, 2001. Yet, at the time it occurred, the attack loomed as large on the American landscape as the towers themselves once did on the Manhattan skyline. The attack killed six people and injured more than a thousand, the first casualties from foreign terrorists on U.S. soil. American authorities identified at least eight perpetrators, but questions remain as to the ultimate cause of the attack.

The attack and its aftermath. At 12:18 p.m. on Friday, February 26, 1993, an explosion rocked the second level of the parking basement beneath Trade Tower One. The explosive material, as investigators would later determine, was somewhere between 1,200 and 1,500 pounds (544–680 kg) of urea nitrate, a homemade fertilizer-based explosive.

The blast ripped open a crater 150 feet (46 m) in diameter and five floors deep, rupturing sewer and water mains and cutting off electricity. Over the hours that followed, more than 50,000 people were evacuated from the Trade Center complex. A stunned nation soon grasped a fact larger than the incident itself: foreign-sponsored terrorism—which had long plagued Western Europe and parts of the Middle East, Africa, and Asia—had come to the United States.

Investigation and cleanup begins. The first analysis team to arrive came from the Federal Bureau of Investigation (FBI), who soon brought in two examiners from the FBI Laboratory Explosives Unit. Over the week that followed, a team of more than 300 law-enforcement officers from various agencies throughout the country would sift through some 2,500 cubic yards (1,911 cubic meters) of debris weighing more than 6,800 tons (6,909 tonnes).

At the same time that this forensic investigation began, government authorities rushed to protect against physical, chemical, and biological hazards associated with the blast. The explosion had exposed raw sewage, asbestos, mineral wool, acid, and fumes from automobiles. Meanwhile, small electrical fires burned, and pieces of concrete and sharp metal hung threateningly from distended beams.

On Saturday, authorities installed seismographic equipment, cleared the area, and conducted a test run of an empty subway train. The results showed that with a few adjustments, the area could be rendered safe for the operation of the Port Authority Transportation system (PATH) on Monday, thus preventing a virtual shutdown of lower Manhattan. The Environmental Protection Agency and the Occupational Safety and Health Administration began taking steps to clean up biological and chemical debris.

Tracking the killers. Meanwhile, the forensic investigation expanded, with two chemists each from the FBI, ATF (Bureau of Alcohol, Tobacco, and Firearms), and New York Police Department collecting and studying residue from the blast area. In the course of this work, investigators found a key piece of evidence: a 300-pound (136-kg) fragment of a vehicle that, based on the damage it had sustained, must have been at the very epicenter of the blast. Sewage contamination had rendered it unusable for residue analysis, but it bore something much better: a vehicle identification number (VIN).

This was not to be the first fortunate break for investigators. Authorities traced the vehicle to a Ryder truck rental facility in Jersey City, New Jersey, from which it had been reported stolen. On Monday, while FBI special agents were at the Jersey City facility to speak with personnel there, the Ryder clerk received a call from a man identified as Mohamed Salemeh. The latter demanded the return of

his $400 deposit for the van in question, and the Ryder clerk arranged for him to return and collect the deposit on March 4, 1993. When Salemeh arrived, he was arrested.

A search of Salemeh's belongings led investigators to Nidal Ayad, a chemist working for the Allied Signal Corporation in New Jersey. Toll records and receipts helped lead to a safe house in Jersey City, New Jersey, where authorities found traces of nitroglycerine and urea nitrate. They also uncovered evidence that Salemeh and Ayad had obtained three tanks of compressed hydrogen gas, and in the course of searching a storage room rented by Salemeh, investigators found large caches of urea, sulfuric acid, and other chemicals used in making a bomb. On March 3, the New York Times received a letter claiming responsibility for the bombing, and subsequent investigation of DNA samples matched Ayad with the saliva on the envelope flap.

Conviction—and continuing questions. The trail of investigation would eventually lead to Ramzi Yousef, who authorities believe was in the van that delivered the explosives to the WTC. With him was Eyad Ismoil. Also implicated in the bombing, along with Salemeh and Ayad, were Ahmad Ajaj, Mahmoud Abouhalima, and Abdul Rahman Yasin. On March 4, 1994, a jury found Salemeh, Ajaj, Abouhalima, and Ayad guilty on 38 counts, including murder and conspiracy, and the judge handed down multiple life sentences.

Yousef fled the country, and engaged in other terror plots before he was captured and brought to the United States from Pakistan in February 1995. He was sentenced to life plus 240 years. As of 2003, Yasin had not been captured, and was believed to be in Iraq. In October 1995, Sheikh Omar Abdel Rahman, a blind Egyptian cleric who taught at mosques in Brooklyn and New Jersey, was sentenced to life imprisonment for masterminding the attack. But some observers wonder whether the roots of the 1993 WTC attack run much deeper.

The fact that Yousef is the nephew of Khalid Sheikh Mohammed, a top figure in al-Qaeda, suggests a strong connection between the 1993 conspirators and the group who ultimately brought down the towers eight years later. After the September 2001, attack, it was the opinion of many investigators and analysts inside President George W. Bush's administration, that the perpetrators of that attack had a state sponsor—Iraq. A number of details, including the fact that Yousef was traveling on an Iraqi passport, as well as the date of the 1993 attack—the second anniversary of the U.S. liberation of Kuwait in the Persian Gulf War—furthered suspicions of Iraqi involvement in the 1993 incident. Mohammed was later involved in masterminding the terrorist attacks on the World Trade Center in 2001, and was arrested in Rawalpindi, Pakistan on March 1, 2003.

World Trade Center

The Columbia Encyclopedia, 6th ed.

Copyright The Columbia University Press

World Trade Center, former building complex in lower Manhattan, New York City, consisting of seven buildings and a shopping concourse on a 16-acre (6.5-hectare) site; it was destroyed by a terrorist attack on Sept. 11, 2001. Prior to its destruction, the World Trade Center had been the world's largest commercial complex, home to many businesses, government agencies, and international trade organizations. Most prominent among its structures were the 110-story rectangular twin towers, one rising to 1,362 ft (415 m) and the other to 1,368 ft (417 m), with floors roughly an acre in size. Designed by Minoru Yamasaki and Emery Roth, the towers and concourse portion of the center were completed in 1973 at a cost of some $750 million. For a brief period (until the completion of the Sears Tower, now the Willis Tower, in Chicago in 1974), the World Trade towers were the tallest buildings in the world. They remained the largest structures on the Eastern Seaboard of the United States, an internationally known landmark and tourist attraction rising high above the skyline of lower Manhattan.

In 1993 a terrorist car-bomb explosion damaged portions of the complex, killing six people and causing more than $300 million in damage. Sheik Omar Abdel Rahman and nine other Islamic extremists were convicted of conspiracy and other charges related to the bombing in 1993, and the so-called mastermind, Ramzi Yousef, was convicted in 1998. On Sept. 11, 2001, a second terrorist attack, in which two hijacked commercial jetliners were crashed into the towers, ignited huge, intense fires in the upper stories of both buildings, weakening them and leading to their collapse. Other structures in the complex were completely or partially destroyed as a result, and many surrounding buildings were severely damaged. More than 2,700 people, including the passengers and crew of the airliners and several hundred emergency personnel responding to the initial fires, lost their lives; more than 7,000 people were injured.

The enormity of the events of Sept. 11 (see also 9/11), which also involved a similar attack with a hijacked jetliner on the Pentagon in Washington, D.C., and the crash in W Pennsylvania of a fourth hijacked plane, galvanized national feeling in the United States, where many watched the events unfold on television. In the aftermath of the worst terrorist attack in history, President George W. Bush announced a war on terrorism, and many nations pledged their support. Al Qaeda, headed by Osama bin Laden, was identified by U.S. authorities as being behind the attacks, and the United States subsequently began military operations in Afghanistan, where bin Laden was based and where the government was closely allied with him.

In Dec., 2001, Zacarias Moussaoui, a Frenchman of Moroccan descent who had been arrested (Aug., 2001) on immigration violations in Minnesota, was indicted on charges that he was part of the conspiracy responsible for the September attacks. He pleaded guilty in 2005 to being part of a conspiracy to attack the White House in a similar manner but denied being part of either Sept. 11 attack, and was given a life sentence in 2006.

The alleged mastermind of the plot was Khalid Sheikh Mohammed, a Kuwaiti of Pakistani parentage who had become a high-ranking member of Al Qaeda. He was captured in Pakistan in 2003, held by the United States at an undisclosed location, and transferred to Guantánamo Bay in 2006. According to a censored transcript of a closed-door hearing in 2007, he admitted to organizing and supervising the execution of the attacks of Sept. 11, but the government also later revealed that he had been subjected to waterboarding, which is generally regarded as a form of torture. In 2008 the Pentagon announced that a military tribunal would try Mohammed and others held at Guantánamo on conspiracy and other charges relating to the attacks; later plans (2010) for a federal trial were abandoned in 2011 in the face of strong political opposition. The five suspects were formally charged in 2012. Bin Laden, who had approved the attacks and eluded capture by U.S. forces in Afghanistan in the months following the attacks, was killed in May, 2011, during a raid by U.S. forces on the house in Abbottabad, Pakistan, in which he was living in hiding.

In the aftermath of the center's destruction, many competing interests—the city and state of New York, the owners of the site, the buildings' developer, survivors of the attack and families and friends of those killed, and others—advocated a variety of approaches to rebuilding the site. After a lengthy design competition, a preliminary master construction plan for the site, by Daniel Libeskind, was approved in 2003. The design has since been much modified, and a new overall plan was unveiled in 2006.

Embracing the ground where the towers stood is a tree-filled street-level plaza that opened in 2011. The towers' footprints are the focus of the memorial; waterfalls stream over sunken black granite walls that edge square voids, feeding two pools below whose centers are smaller, echoing voids; the names of those who died are cut into bronze panels that surround the pools. The plaza was designed by Peter Walker; the memorial by Michael Arad. The plaza also contains the trapezoidal entrance to an underground memorial museum, which opened in 2014. Surrounding the memorial will be a group of office towers that rise in height toward the the
"Freedom Tower"
(Tower 1), designed by the American architect David M. Childs of Skidmore, Owings and Merrill and opened in 2014. Tower 2 is being designed by England's Lord Norman Foster, Tower 3 by another English architect, Lord Richard Rogers, and Tower 4 by Japan's Fumihiko Maki. The complex will also include a transportation hub by Spain's Santiago Calatrava and a performing arts center.

World Trade Center, 1993 Terrorist Attack

World of Forensic Science
COPYRIGHT 2005 Thomson Gale

World Trade Center, 1993 Terrorist Attack

The World Trade Center (WTC) bombing of 1993 has since been overshadowed by the attack that brought the twin towers down on September 11, 2001. Yet, at the time it occurred, the attack loomed as large on the American landscape as the towers themselves once did on the Manhattan skyline. The attack killed six people and injured more than one thousand.

The law enforcement response to the tragedy involved a massive forensic investigation designed to determine the cause of the blast, the identities of
those responsible and, ultimately, to ascertain why, although Trade Tower One sustained a great deal of damage, it did not collapse. The forensic sleuthing involved the detailed examination of the blast scene, physical and chemical analyses of samples, and forensic accounting to trace a paper trail that led to the suspects.

At 12:18 p.m. on Friday, February 26, 1993, an explosion rocked the second level of the parking basement beneath Trade Tower One. The explosive material, as forensic investigators would later determine in their chemical analyses of samples retrieved at the site, was somewhere between 1,200 and 1,500 pounds (544–680 kg) of urea nitrate, a homemade fertilizer-based explosive.

The blast ripped open a crater 150 feet (46 meters) in diameter and 5 floors deep, rupturing sewer and water mains and cutting off electricity. Over the hours that followed, more than 50,000 people were evacuated from the Trade Center complex.

The first forensic analysis team to arrive was from the Federal Bureau of Investigation (FBI ). The bureau brought in two examiners from the FBI Laboratory Explosives Unit. Over the week that followed, a team of more than 300 law-enforcement officers (including forensic specialists) from various agencies throughout the country would sift through some 2,500 cubic yards of debris weighing more than 6,800 tons.

At the same time that this forensic investigation began, government authorities rushed to protect against physical, chemical, and biological hazards associated with the blast. The explosion had exposed raw sewage, asbestos, mineral wool, acid, and fumes from automobiles. Meanwhile, small electrical fires burned, and pieces of concrete and sharp metal hung threateningly from distended beams.

On Saturday, authorities installed seismographic equipment, cleared the area, and conducted a test run of an empty subway train. The results showed that with a few adjustments, the area could be rendered safe for the operation of the Port Authority Transportation system (PATH) on Monday, thus preventing a virtual shutdown of lower Manhattan. The Environmental Protection Agency and the Occupational Safety and Health Administration began taking steps to clean up biological and chemical debris.

Meanwhile, the forensic investigation expanded, with two chemists each from the FBI, ATF (Bureau of Alcohol, Tobacco, and Firearms), and the New York Police Department collecting and studying residue from the blast area. In the course of this work, investigators found a key piece of evidence : a 300-pound (136-kg) fragment of a vehicle that, based on the damage it had sustained, must have been at the epicenter of the blast. Sewage contamination had rendered it unusable for residue analysis, but recovery of a vehicle identification number allowed the vehicle to be traced.

Authorities traced the vehicle to a Ryder truck rental facility in Jersey City, New Jersey, where it had been reported stolen. On Monday, while FBI special agents were at the Jersey City facility to interview personnel there, a Ryder clerk received a call from a man identified as Mohammed Salameh. The latter demanded the return of his $400 deposit for the van in question, and the Ryder clerk arranged for him to return and collect the deposit on March 4, 1993. When Salameh arrived, he was arrested.

A search of Salameh's belongings led investigators to Nidal Ayyad, a chemist working for the Allied Signal Corporation in New Jersey. Forensic accounting of toll records and receipts helped lead to a safe house in Jersey City, New Jersey, where authorities found traces of nitroglycerine and urea nitrate. They also uncovered evidence that Salameh and Ayyad had obtained three tanks of compressed hydrogen gas. In the course of searching a storage room rented by Salameh, investigators found large caches of urea, sulfuric acid, and other chemicals commonly used in making bombs. On March 3, the New York Times received a letter that claimed responsibility for the bombing. A subsequent forensic investigation of DNA samples matched Ayyad with the saliva on the envelope flap.

A forensic investigation was conducted to examine how such a massive blast failed to collapse the tower. The consensus opinion is that the location of the explosion, on the second level of the underground parking lot, acted to diffuse the intensity of the explosion. When the concrete floor of that level ruptured, much of the force of the blast was directed downward into the lower levels of the parking garage.

World Trade Center

Dictionary of American History
COPYRIGHT 2003 The Gale Group Inc.

WORLD TRADE CENTER

WORLD TRADE CENTER, a seven-building complex that was located on a sixteen-acre site in lower Manhattan in New York City. The Port Authority of New York and New Jersey financed the $958 million cost of construction. The architect Minoru Yamasaki designed the two 110-story towers (numbers 1 and 2 World Trade) in the International Style; the Twin Towers, as they were called, were to be the tallest buildings in the world, a record they held in 1973. To achieve that height, the engineering firm of Worthington-Skilling recommended a tube structure in which columns on the exterior walls, and the inner core of the skyscrapers, bore the gravity load. A grill of lightweight steel trusses connecting the perimeter and core supported the floors. Given the proximity of the Twin Towers to two major airports, each tower was built to withstand the impact of a Boeing 707 aircraft.

Relying on the perimeter and core columns to provide vertical support created 10 million square feet of open commercial space, which was leased to import and export businesses, government agencies, financial firms, and restaurants. Groundbreaking occurred in 1966; tenants moved into the World Trade Center in December 1970. The last building in the complex, 7 World Trade, a forty-seven story building, was completed in 1985.

On 23 February 1993, a truck bomb tore through an underground parking garage beneath the Vista Hotel (3 World Trade), killing six people. The explosion produced a crater six stories deep and destroyed lateral supports throughout the damaged area. As a result of the bombing, building modifications were introduced to improve evacuation, with tenants receiving evacuation training, and additional

fire command centers were established in the lobbies of the Twin Towers. On 11 September 2001, two hijacked Boeing 767 commercial airliners were flown into the Twin Towers, causing the collapse of both skyscrapers; 2,830 people, including 403 emergency personnel, died.

The Federal Emergency Management Agency (FEMA) led the effort in trying to determine the progression of the collapse, a task complicated by the removal of the beams to recycling centers and scrapyards during the recovery effort. The prevailing hypothesis is that the impact of the airliners sheared off the fireproofing on the trusses, which softened in the subsequent blaze; jet fuel pouring into the elevator shafts spread the fires to lower decks. With the integrity of the sagging floors compromised, it is believed that an unsupportable gravity load was redistributed to the core columns, leading to total structural failure. The damage of the initial impact was also being assessed.

Eight surrounding buildings either partially or totally collapsed that day, crushed by falling debris (3 World Trade) or gutted by fire (7 World Trade). Discussions about the future use of the site, referred to as "Ground Zero"—whether it should be dedicated solely as a memorial or reopened for mixed-use purposes—were ongoing at the end of 2002.